Android网络相关辅助类 NetUtils

 import android.app.Activity;  
import android.content.ComponentName;  
import android.content.Context;  
import android.content.Intent;  
import android.net.ConnectivityManager;  
import android.net.NetworkInfo;  
  
/** 
 * 跟网络相关的工具类 
 *  
 *  
 *  
 */  
public class NetUtils  
{  
    private NetUtils()  
    {  
        /* cannot be instantiated */  
        throw new UnsupportedOperationException("cannot be instantiated");  
    }  
  
    /** 
     * 判断网络是否连接 
     *  
     * @param context 
     * @return 
     */  
    public static boolean isConnected(Context context)  
    {  
  
        ConnectivityManager connectivity = (ConnectivityManager) context  
                .getSystemService(Context.CONNECTIVITY_SERVICE);  
  
        if (null != connectivity)  
        {  
  
            NetworkInfo info = connectivity.getActiveNetworkInfo();  
            if (null != info && info.isConnected())  
            {  
                if (info.getState() == NetworkInfo.State.CONNECTED)  
                {  
                    return true;  
                }  
            }  
        }  
        return false;  
    }  
  
    /** 
     * 判断是否是wifi连接 
     */  
    public static boolean isWifi(Context context)  
    {  
        ConnectivityManager cm = (ConnectivityManager) context  
                .getSystemService(Context.CONNECTIVITY_SERVICE);  
  
        if (cm == null)  
            return false;  
        return cm.getActiveNetworkInfo().getType() == ConnectivityManager.TYPE_WIFI;  
  
    }  
  
    /** 
     * 打开网络设置界面 
     */  
    public static void openSetting(Activity activity)  
    {  
        Intent intent = new Intent("/");  
        ComponentName cm = new ComponentName("com.android.settings","com.android.settings.WirelessSettings");  
        intent.setComponent(cm);  
        intent.setAction("android.intent.action.VIEW");  
        activity.startActivityForResult(intent,0);  
    }  
  
}